Unit 6 Animal Nutrition

Unit 6

 Feeding of Laboratory & wild animals and Metabolic Disorders

1.  Feeding Practices for Swine

2. Feeding Practices for poultry

3. Feeding Practices for laboratory animals

4. Metabolic Disorder  & symptom 

1.  Feeding Practices for swine 

• Hind gut fermenter

• Fermentation- caecum and Colon

• VFA- 35-45% maintenance requirements (60% in ruminants)

• Weaning- 8 weeks.

• Crude Fibre- growing- 6-7% and 10-12% adult pig.

• Pigs less than 2 to 3 weeks old have insufficient pancreatic amylase and intestinal

disaccharidases. Hence after 2 weeks of age only, pigs are to be fed starch-or

cereal-based diets.

• Feed efficiency- 30-40% heritable. Best feed efficiency

• ME = 0.96 DE

• Pig- 1st limiting AA- lysine

• Birth weight: 0.7 – 1 kg

• Essential amino acid in pigs: 9 (arginine not essential)

• Iron dextran injection (i/m) is to be given on 4th and 14th day of age to prevent piglet anemia.

• FeSO4 2% of feed

Creep feed:

•  Creep (pre-starter) feeding system is essential for sucking piglets for faster growth and attain their satisfactory weaning weight.

•  Piglets are weaned at 6 weeks of age in western countries and at 8 weeks of age in India under an intensive feeding system.

•  Creep mixtures are introduced at 7-14 days of age and are fed till weaning.

•  Piglets fed on creep ration attain 12-15 kg body weight at 8 weeks of age.

•  During the suckling period piglets are more prone to piglet anemia, creep feed is generally mixed with ferrous sulfate at the ratio of 9:1 to prevent anemia.

•  Composition of creep feed (BIS, 1986): CP, min = 20% and ME (kcal/kg), min = 3265

Grower ration:

•  After creep feed on attainment of 12-15 kg of body weight at 8 weeks of age piglets are shifted on grower ration.

•  At this stage, pigs consume considerably more feed and attain around 35 kg in indigenous and 50kg BW in exotic breeds.

•  Grower ration should have 18% CP and 3170 kcal/kg ME value.

Finisher/breeder ration:

•  On attainment of grower bodyweight pigs are switched over to finisher ration.

•  Finisher ration should contain 16% CP and 3170 kcal/kg ME value.

•  For the indigenous pigs, slaughter at about 45-50 kg is recommended (IVRI, 1993).

•  Pigs grow around 700 g/day so they can attain 100 kg of body weight in 143 days.

•  Breeder pig required a finisher ration with a higher level of vitamins.

Feeding of pregnant sow:

•  Feeding of pregnant sows is recommended as breeder pigs but feed offered needs to be restricted to 2-2.5 kg/day, because higher quantity of feed may lead to embryonic mortality.

•  Ration should contain 16% CP and 3000 kcal/kg ME value with 0.7% lysine.

Feeding of lactating sows:

•  It should be offered additional feed for early recovery of the body condition (body weight loss) and for milk production.

•  For a lactating gilt 2.0 kg of meal with 200g meal per piglet in the litter may be sufficient to meet nutrient requirement.

Flushing ration:

•  A well-balanced high protein ration before breeding is required for flushing to obtain greater litter size & body weight.

•  This ration is given to gilt or sows, 15 days before mating to proper conceiving.

•  During gestation period, sows are fed on restricted feeding (2-3 kg) without getting overweight.

•  On the day of farrowing, 250g of wheat bran could be offered for proper lactation.

Feeding of piglets:

1.  Colostrum feeding

•  It is the first milk and an essential source of energy, nutrients & immunity for the piglets.

•  It is important to maximize colostrum intake in the first six hours after birth (150-280 ml/kg of birth BW)

2.  Milk replacer:

•  A milk replacer for piglets is a good solution to supply piglets with extra nutrients and energy, when sow milk supply is not sufficient.

•  The ingredient of milk replacer should be of higher quality and easily digestible since we are feeding a young one.

Use of unconventional feedstuff in pig ration:

• Feed cost of pig production usually accounts for nearly 60-70% of the total production cost.
• It is extremely important that an economical as well nutritionally balanced diet be provided during all stages of production.

Common available unconventional feedstuff:

• Sweet potato- fed as an energy source in pig ration.
• Pineapple waste- waste obtained after squeezing juice contains 5% CP and also fed as an energy source.
• Tapioca waste/ cassava root – it can be used as an energy source in ration up to 5-10%.
• Decaffeinated tea waste – It contains about 7.5% DCP and can be used up to 10% in concentrate feed.
• Garbage waste- wastes from hotel, hostels, kitchen & agricultural wastes can be used in pig ration, before feeding waste should be boiled properly.

2.  Feeding Practices for poultry

General Principal/ guidelines/ facts for Poultry feeding:

•      Feed must contain all essential nutrients in the right amounts & proportion required.

•      Different standards per age should be followed.

•      Palatability of the ingredients, which are used.

•      Unlike ruminants, poultry completely depend upon the dietary sources for all nutrients (essential AA., Vit. B groups and K).

•      Include agro-industrial by-products to minimize cost of the ration,

•      Optimum level of ingredient inclusion as many of ingredients have a deleterious effect at higher levels.

•      Optimum Ca:P ratio for different purposes.

Factors affecting feed intake in poultry:

•      Energy levels in the ration:

•      Increase in energy level → decrease in feed intake and vice versa.

•      Environmental temperature: (16-24^oC): Increase in Temp. = decrease in feed intake and vice versa.

•      Health of the bird

•      Genetics

•      Form of the feed

•      Nutritive balance of the diet

•      Stress

•      Body size

•      Rate of growth & egg production 

Nutrients requirements of poultry:

Energy requirement:

•      Ration for poultry calculated based on ME.

•      Poultry eat to satisfy their energy needs when fed free choice, thus must control the intake of all nutrients by including them in a definite proportion to available energy level.

•      High-energy cereal grains are the principal energy sources.

•      Fat may be added at levels of 3-8% to increase dietary energy concentrations.

Protein requirement:

•      The amount of protein required is proportional to the energy level in the ration.

•      Poultry requires the 11 essential AAs.

•      Increase in Temp. = decrease in feed intake = increase in protein requirement and vice versa.

•      Some AAs can be met by other AAs: Cystine = methionine, Tyrosine → phenylalanine, Glycine = Serine.

•      Overheating or under-heating during processing can affect the availability of some amino acids.

Mineral requirements:

•  The major minerals needed in poultry diets are Ca, P, Na & Cl. Trace minerals are added to diets deficient in them.

•  The recommended ratio P: Ca in the diet of poultry is 1:1.2 (range 1:1 to 1:1.5). For laying hen 1:4 (Ca important for bone & shell formation)

•  Inorganic P have a higher availability than organic P. All P from animal origin & 40% from plant origin (wheat bran & rice bran) is available.

•  The amount of Salt (NaCI) added depends upon the feed ingredients. The recommended level in the ration 0.5-1% of the ration. Adult poultry can tolerate much higher inclusion but the water consumption increased. Manganese is required to avoid slipped tendon disease in poultry.

Vitamin requirements:

•  All the vitamins have their specific role in the health of the poultry birds. Liberal amount of each vitamin is required to avoid specific disease conditions related to them.

Nutrients requirement in Broilers feeds as per BIS (2007)

.	Characteristic	Requirement for broiler feed
		Pre-starter	Starter	Finisher
1	Moisture % by mass, Max.	11	11	11
2	CP % by mass, Min.	23	22	20
3	EE % by mass, Min.	3.0	3.5	4.0
4	CF % by mass, Max.	5.0	5.0	5.0
5	AIA % by mass, Max.	2.5	2.5	2.5
6	Salt (NaCl) % by mass, Max.	0.5	0.5	0.5
7	Ca % by mass, Min.	1.0	1.0	1.0
8	Total P % by mass, Min.	0.7	0.7	0.7
10	Available P % by mass, Min.	0.45	0.45	0.45
11	Lysine % by mass, Min.	1.3	1.2	1.0
12	Methionine % by mass, Min.	0.5	0.5	0.45
13	ME (kcal/kg), Min.	3000	3100	3200
14	Aflatoxin B1 (ppb)	20	20	20

Phase feeding in layers

Purpose: To adjust nutrient intake in accordance with the rate of egg production

•  In egg production hen usually cover a period of 15 months
• Egg production commences at 20-22 weeks of age, peak at 28-30 weeks of age gradually decline to 65% after 60 weeks and nearly cease at around 72 weeks of age.
• Effect of light exposure: lighted period = increase feed intake & increased stimulation of pituitary gland = increase in egg laid. 

Phase I (from 22-42 week of age): Most critical period

•  Increase in egg production from zero to peak (85-90% production).
•  Increase in body weight from 1300 to 1900g.
• Increase in egg size from 40g/egg at 22 weeks to over 56g/egg at 42 weeks of age.
• Protein and ME are comparatively lower than chick stage (up to 8 weeks) but higher than grower stage (8 to 20 weeks).
• Calcium requirement increases three times to support egg production.

Phase II (from 42-72 week of age):

• Period after 42 wk of age when the hens attained mature body weight to about 72 wks of age.
• Protein and ME requirement during Stage II is comparatively lower than Stage I.
• Calcium requirement increases further to 3.5% of feed.

Nutrients requirement in Layer feeds as per BIS (2007)

.	Characteristic	Requirement for laying birds feed
		Chick	Grower	Layer Phase I	Layer Phase II
1	Moisture % by mass, Max.	11	11	11	11
2	CP % by mass, Min.	20	16	18	16
3	EE % by mass, Min.	2.0	2.0	2.0	2.0
4	CF % by mass, Max.	7.0	9.0	9.0	10.0
5	AIA % by mass, Max.	4.0	4.0	4.0	4.5
6	Salt (NaCl) % by mass, Max.	0.5	0.5	0.5	0.5
7	Ca % by mass, Min.	1.0	1.0	3.0	3.5
8	Total P % by mass, Min.	0.65	0.65	0.65	0.65
9	Available P % by mass, Min.	0.40	0.40	0.40	0.40
10	Lysine % by mass, Min.	0.6	0.7	0.7	0.65
11	Methionine % by mass, Min.	0.40	0.35	0.35	0.30
12	ME (kcal/kg), Min.	2800	2500	2600	2400

3. Feeding Practices for laboratory animals

• Nutrient requirements vary based on species, strain, age, reproductive status, and experimental conditions.
• Commercially manufactured diets are preferred as they are more uniform, contaminant-free, and have known shelf life.
• Laboratory animals typically consume 4-6% of their body weight in food daily, with most small animals fed ad libitum.
• Protein requirements range from 12-18% for growing animals to 5-7% for maintenance in adult rats.
• Essential fatty acids like n-3 fatty acids are required at about 0.4% of dietary metabolizable energy for rats.
• Calcium and phosphorus are important minerals that should be provided in a 1.2-1.6:1 ratio.
• Vitamins A, D and E are the most critical vitamins, with vitamin E supplementation important for stressed animals.
• Feed should be palatable, uncontaminated, nutritionally adequate, easily accessible, and provided in a way that meets the animal’s behavioral needs.

4. Metabolic Disorder  and Symptom

• Metabolism is sum of Physical and Chemical Metabolic processes relating to absorbance and breakdown or synthesis of necessary organic molecules in body

• Disturbance of one or more metabolic processes related to regulation of a certain metabolites in the body fluids is known as metabolic disorders

• Nutritional diseases -» deficiency, excess or imbalance of

specific nutrients -» metabolic disturbances -» metabolic disorder

• Mostly occur after parturition

• Transition period—Dry  lactation

Influencing factors are

1. Hormonal changes

2. Moving from non-lactating to lactating stage- lactation stress

3. Changing of diet from roughages to highly fermentable CHO.

Metabolic Diseases

1) Fatty liver

2) Ketosis

3) Acidosis (SARA)

4) Laminitis

5) Milk fever

6) Downer cow

7) Retained placenta

8) Bloat

9) Grass tetany

10) LDA

11) Udder edema

ALL THE METABOLIC DISEASES ARE RELATED TO ONE ANOTHER

Fatty Liver

• Common metabolic disorder during transition period.

• Up to 65% of dairy animals are affected by moderate or severe fatty liver during early lactation

• Reason- Over conditioned animals during dry period (BCS>4.5)

• NEBAL-body fat is mobilized from adipose tissue into the bloodstream in the form of NEFA

• NEFA are taken by the liver in proportion to their supply, but the liver does not have capacity sufficient to oxidize and use all amounts of NEFA for energy.

• Therefore, cows are predisposed to accumulate NEFA as triglycerides within the liver.

Preventatives for fatty liver

• Avoid excessive fattening during dry period by providing relatively low- energy, low-protein forages until the last few weeks of pregnancy.
• Glucogenic sub- glycerol, propylene glycol, monensin.
• B-complex vitamins are sometimes used in cases of fatty liver disease to supply cofactors of metabolism and to help stimulate the animal’s appetite.
• Vitamin E and selenium- as their antioxidant effects help protect the liver Lipotropic agents (choline, methionine)- remove fat from liver cells, slow down fat deposition.

Ketosis (Acetonemia)

• In dairy cows, ketosis is a lactation disorder usually associated with intense milk production and NEBAL (6-8 wk postpartum)
• An increase of “ketone bodies” in blood until they eventually begin to spill over into urine and (or) milk.
• Acetone, Acetoacetate, and β-Hydroxybutyrate Acetone: smell from breath

Source of Ketones

1) From butyrate produced in the rumen and converted to beta- hydroxybutyrate by rumen mucosa during absorption

2) From metabolism in liver of LCFA primarily released from adipose tissue during energy deficit

Ketogenesis

• Normally- FFA are oxidized to the normal intermediate acetoacetyl-CoA, which further is oxidized to CO2 and acetyl-CoA in the citric acid cycle

• Ketosis- acetoacetyl-CoA – -» Acetoacetate

1. By Acetoacetyl-CoA deacylase (ruminant liver and kidney)

2. By Hydroxymethylglutaryl- CoA synthase and hydroxymethylglutaryl-CoA lyase pathway (liver and rumen epithelium)

Acetoacetate is converted to other ketone bodies i.e. Acetone or β- hydroxybutyrate

Predisposing factors

• Glucose deficiency (NEBAL)- 60 to 85% of the available glucose drains as lactose in milk. Glucose demand exceeds gluconeogenesis in the liver resulting in increased ketogenesis.

• Excessive fattening/ BCS- pre-partum

• Lactation demand- conducive to excess fat mobilization, which contributes to ketosis.

• Deficiency of ACTH- impaired gluconeogenesis

• Deficiency of OAA- Gluconeogenic

Sign and symptoms

• Loss of appetite, refusing grain and eating only small amounts of roughage, acetone smell in breath.

• A few affected cows will show nervous symptoms.

• Characterized by hypoglycemia- from a normal of 50 to 60 to as little as 25 mg/100 ml.

• Hyperketonemia- from a normal of less than 10 to as high as 50 mg/l00 ml blood

• Other frequently observed changes include increases in NEFA, decrease in liver glycogen and increases in liver lipid that can lead to liver damage.

Treatment

• Intravenous injection of glucose (50% dextrose)

• Intramuscular glucocorticoid (Isoflupredone)

• Gluconeogenic precursor- Sod. Propionate, glycerol, propylene glycol

• Supportive- vitamins

Ruminal Acidosis

• Important nutritional metabolic disorder common in the field especially in high yielding cows with high grain ration.

• Grain engorgement

• Sudden change in diet- Dry cow is fed a high forage ration that is less energy dense and higher in NDF than the lactating animal

• Ruminal populations ill-suited to energy rich ration

Acidosis vs SARA

• Ruminal acidosis (pH<5.5)- when animal consumes excess of grain or due to lactate accumulation

• SARA (pH<6)- excessive VFA production that exceeds ability of rumen papillae to absorb them and is commonly seen at calving when dry cow is switched to grain ration (smaller

rumen papillae). 

Prevention

• Balancing the diet for starch and effective fibre.

• Sudden changes of feed and slug feeding of grain and/or molasses should be avoided.

• Roughages should be provided with grain/molasses.

• Buffers such as sodium bicarbonate also counteract acidosis

Laminitis

• Pathological disturbance of microstructure of sensitive laminae of hoof.

• Seen in high-production, intensively managed cattle

• Acidosis affects Gram negative bacteria- toxins

• Endotoxins and histamine released as the rumen flora die, are absorbed systemically and affect the microvasculature of the hoof wall and result in clinical laminitis.

Prevention

• Avoid abrupt switch from dry-off ration to high lactation ration

• Foot baths- 2–5% copper sulphate.

• Nutritional supplements- biotin and zinc – help in keratinization.

• Vitamin A and vitamin E- important roles in maintaining claw integrity.

• Other trace minerals that impact claw condition include I, Se, Cu, Mn and Co.

Milk fever/Parturient Paresis (hypocalcemia)

• An afebrile hypocalcemic disease of cattle usually associated with parturition and initiation of lactation in high producing animals when the demand of calcium for milk production exceeds the body’s potential to mobilize calcium reserves.

• Low blood calcium level interferes with muscle function causing general weakness, depression and death.

Etiology:

• It is more common in older dairy cows (reduced ability to mobilize calcium from bone and in high milk producing breeds due to exhausted reserves)

• Lactation (usually first 72 hr postpartum)- Ca drain (10 mg/dl to 5 mg/dl)

• Parathyroid inactivity and dietary Ca supplementation during dry period

Clinical Signs

• Body temperature – subnormal (100-101oF)

• Neck curved towards the flank

• Cold extremities

• In-coordination, wobbly and weak

• Occasionally, hyperexcitability

Prevention and treatment

• DCAD- addition of anions to the diet of dairy cows prior to parturition effectively reduced the incidence of milk fever by inducing a metabolic acidosis, which keeps parathyroid hormone in active state thus reducing incidence of fever milk.

• Anionic Min. Mixture during transition period

• Avoid Pre-partum diets high in cations- Na+ and K+

• Restoration of Ca– half i/v and half s.c. in multiple sites – Retreat 8-12 hr later, if needed.

• Ca gel orally 1 day before and I day after calving

• Vit. D- 8 days before calving, s.c.

Downer cow syndrome/complex

• Downer cow syndrome is a complication of periparturient hypocalcemia in cows that do not fully respond to calcium therapy and are unable to rise for >24 hr after initial recumbency.

• The animal may develop a secondary recumbency from pressure damage to muscles and nerves.

• Many peripartum diseases (milk fever, acidosis, fatty liver, displaced abomasum etc.) are interrelated with one another, they have been grouped under the general title “downer cow complex.”

Retained placenta

Failure of fetal membranes to be expelled from the uterus within 12 to 24 hours after parturition

Etiology:

• Increased incidence with over conditioning and hypocalcemia

• Dystocia and twinning increases incidence of retained placenta

• Extreme deficiency of dietary energy, protein or both can result in RP.

• The rate of RP is associated with imbalances in Ca and P metabolism.

• Se and vitamin E- important for reducing the incidence of RP

• Deficiency of vitamin A and β-Carotene increase the incidence of RP.

Prevention

o Proper nutrition especially during dry period

o Supplementation with selenium

o Adequate amounts of vitamin A and fiber

o Over-conditioned cows are at an increased risk

o Reduce dystocia– by proper management.

Grass tetany/ Hypomagnesaemia

• It is most often associated with animals in early lactation grazing on lush green pastures 
• Rumen is the primary site of absorption of Mg and Low pH enhances Mg absorption while high pH above 6.5 decreases its solubility and rumen absorption.
• Lush green pastures are rich in K+, Na+ and NPN compounds. 
• K+, Na+ have positive DCAD thus alkalize the rumen environment resulting in decreased Mg absorbance. 
• Further degradation of NPN compounds in lush green pastures exceed the capacity of rumen microbes to incorporate in microbial protein resulting in ammonia build up which increases the rumen pH resulting in decreased Mg absorption
• Disease is more severe if accompanied by hypocalcemia
• Tetanic or paretic type and subclinical types with depression of appetite and milk yield, slight nervousness, anemia.
• Treatment- Restoring normal Ca and Mg homeostasis and muscle relaxant
• • Addition of 15-30 g of Mg supplement (MgO) per day usually prevents hypomagnesemic tetany.

Displaced Abomasum

• Dislocation of abomasum to the left (LDA) or to right (RDA) in stomach in relation to normal placing (floor of abdomen)

• Approx. 80-90% of incidences are LDA and most frequent in high producing cows in the first 4 weeks postpartum

• Predisposition- High concentrate, low roughage and diets with smaller particle size, sudden changes in the diet and hypocalcaemia in early lactation

• Transition period- Reduced feed consumption and inadequate filling of the rumen- empty space appears for movement of abomasum which therefore does not reach the ventral abdominal

wall

• Low ruminal VFA absorption (papillae)- escape to abomasum, reduce abomasal motility, development of atony and onset of displaced abomasums.

Prevention-

• It can be prevented by maintaining the forage to concentrate ratio of the diet fed in late gestation and early lactation and feeding TMR.

• Grain intake after calving should be increased slowly (0.25 kg/day) until peak grain intake is achieved.